To describe the sequential appearance of healing rib fractures on initial and follow-up radiographs using published guidelines in approximating the age of rib fractures in infants with the aim of establishing a more objective method of dating rib fractures by measuring the thickness of the callous formation. The thickness of the callous formation follows a predictable pattern advancing one stage after a 2-week follow-up with progressive callous thickening starting from stage 2, peaks at around stage 4, and then tapers and remodels until it almost disappears when the fracture is healed at stage 6. Patients with osteogenesis imperfecta, known vitamin D deficiency, and skeletal or metabolic dysplasia were not included in the study. Check if you have access through your login credentials or your institution. Sixteen infants age range months, seven males and nine females with 23 rib fractures were analysed.